From 435d422624b74085e2c0be650dc3a1d3a4a6bfa5 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Thu, 31 Aug 2023 13:17:47 +0200 Subject: ARM: shmobile: sh73a0: Reserve boot area when SMP is enabled CPU core bringup on SH-Mobile AG5 uses the SYS Boot Address (SBAR) and Address Translation Area (APARMBAREA) registers to specify the base address and size of the boot area of the System CPU. With this enabled, when the System CPU accesses a physical address in the range from zero up to the configured size, the top address bits are replaced by those specified in the SBAR register. Hence any device residing in this low part of physical address space cannot be accessed. Prevent conflicts by reserving this memory region using request_mem_region(). Signed-off-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/20eb4e7fca9c41a34500fc5984602b41006b4575.1693409184.git.geert+renesas@glider.be --- arch/arm/mach-shmobile/smp-sh73a0.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'arch/arm/mach-shmobile') diff --git a/arch/arm/mach-shmobile/smp-sh73a0.c b/arch/arm/mach-shmobile/smp-sh73a0.c index 453d48865029..9196b37ea292 100644 --- a/arch/arm/mach-shmobile/smp-sh73a0.c +++ b/arch/arm/mach-shmobile/smp-sh73a0.c @@ -44,10 +44,16 @@ static int sh73a0_boot_secondary(unsigned int cpu, struct task_struct *idle) static void __init sh73a0_smp_prepare_cpus(unsigned int max_cpus) { - void __iomem *ap = ioremap(AP_BASE, PAGE_SIZE); - void __iomem *sysc = ioremap(SYSC_BASE, PAGE_SIZE); + void __iomem *ap, *sysc; + + if (!request_mem_region(0, SZ_4K, "Boot Area")) { + pr_err("Failed to request boot area\n"); + return; + } /* Map the reset vector (in headsmp.S) */ + ap = ioremap(AP_BASE, PAGE_SIZE); + sysc = ioremap(SYSC_BASE, PAGE_SIZE); writel(0, ap + APARMBAREA); /* 4k */ writel(__pa(shmobile_boot_vector), sysc + SBAR); iounmap(sysc); -- cgit